Floor sanding machine

ABSTRACT

A floor sanding machine ( 1 ) has a frame ( 1 ) which carries on its underside a motor-driven, vertically adjustable sanding plate ( 4 ) with a sanding disk, an annular dust suction nozzle ( 11 ) which surrounds the sanding plate, and two front running wheels ( 13 ) and a rear wheel ( 14 ) which support the frame. A controller ( 7 ) analyzes the signals from a laser scanner ( 18 ) for measuring the distance from the sides and front of the sanding machine to the wall and controls by means of a servo system ( 17 ) the rear wheel designed as a tail wheel and a rear wheel driving motor ( 16 ) for moving the sanding machine. The pressure applied by the sanding plate, the sanding plate driving motor ( 9 ) and a sanding dust suction turbine are also controllable by the controller. The sanding dust suction turbine is arranged outside the surface to be sanded, and the dust suction nozzle of the sanding machine is connected by a suspended suction line ( 12 ) to a dust bag of the suction turbine.

The invention relates to a floor sanding machine having a frame which supports a motor-driven, height-adjustable sanding plate with a sanding disk on its underside, with a ring-shaped dust suction nozzle surrounding the sanding plate and with two front running wheels, as well as one rear wheel, supporting the frame, wherein a control device is provided, which evaluates the signals of a distance-measuring arrangement for measuring the lateral and front distance of the sanding machine from the wall, and controls the rear wheel designed as a tail wheel and a rear wheel drive motor by means of a servo device for propelling the sanding machine, wherein a device for adjusting the contact pressure of the sanding plate, as well as the drive motor of the sanding plate, are also controllable by means of the control device.

The demand for floor sanding machines continuously increases because of the increasing use of wood floors instead of wall-to-wall carpeting in residential and business locations, along with the requirement for an efficient and particularly automatically functioning sanding machine connected with this. In particular, there is a requirement for a fully automatic sanding machine which calculates its own position rapidly and precisely.

WO 2004/105998 describes a floor sanding machine, in which the signals from ultrasound sensors are evaluated for measuring the lateral and front distance of the sanding machine from a wall, and in which the rear wheel designed as a tail wheel, and a rear wheel drive motor, are controlled by means of a servo device for propelling the sanding machine. With this known sanding machine the position calculation by means of ultrasound sensors takes place too slowly in some cases, for example in narrow corridors, for matching the sanding arrangement of the sanding machine with the course of the surface to be sanded without delay. A further problem is the result of the arrangement of the dust bag on the sanding machine itself, since the sanding operation must be stopped if the dust bag is too full.

The invention is aimed at providing an improved fully-automatic floor sanding machine capable of sanding a floor of a room, or of connected rooms having a continuous surface, which are mainly made of wood, evenly and without delays.

A floor sanding machine of the type mentioned at the outset, designed in accordance with the invention, is distinguished in that the distance-measuring arrangement has a laser scanner with a laser distance sensor and a rotating mirror, wherein the laser scanner transmits the measuring signals to the control device via a data interface, that a sanding dust suction turbine, which can be controlled by the control device, is arranged outside of the area to be sanded, and the dust suction nozzle of the sanding machine is connected with a dust bag of the suction turbine via a suspended suction line, and that a frame element of the sanding machine supporting the sanding plate is releasably connected with a frame element, which supports the tail wheel together with the rear wheel drive motor.

In accordance with a further characteristic of the invention the sanding plate is connected with a hollow shaft embodied in a cylinder shape and having an opening toward the hollow shaft in its center, wherein the hollow shaft is preferably seated in a guide element attached to the underside of the front frame element.

The rear wheel is seated on the underside of the rear frame element, preferably rotatable by means of a vertical shaft.

An extremely precise, flexible, as well as fully automatic and cost-effective operation of the floor sanding machine becomes possible by the employment in accordance with the invention of a laser sensor. A further advantage of the invention is that it is possible to achieve an interruption-free sanding operation because of the sanding bag being arranged outside of the surface to be sanded, because the size of the sanding bag can be matched to the size of the floor to be processed. At the same time the splitting of the device into two parts which can be separated from each other makes possible simple transport and easy maintenance.

In what follows, the invention will be explained in greater detail by means of an exemplary embodiment, making reference to the drawings. Shown are in:

FIG. 1, a sanding machine in accordance with the invention and in

FIG. 2, schematically the information exchange between a control device of the sanding machine and the components of the sanding machine.

The sanding machine 1 in accordance with the invention has a base frame 2 having two frame elements 2′, 2″, which are releasably connected with each other. The front frame element 2′ has an apron 3 extending around its underside.

A rotating hollow shaft 4 embodied in the shape of a cylinder with a sanding plate 5, which can be driven at a high circumferential speed, for receiving a sanding disk 5′ and having an opening toward the hollow shaft 4 in the center, is seated in a guide element 6. This guide element 6 is attached to the underside of the front frame element 2′.

The contact pressure of the sanding disk 5 is automatically controlled by a control device 7 arranged on the rear frame element 2″ in that the control device 7 evaluates the power consumption of an electric motor 8 which operates the lever mechanism (not represented) of the sanding disk 5 in order to set the electric motor 8 to a predetermined pressure. The transfer of the torque from a sanding disk drive motor 9 seated on the front frame element 2′ to the sanding shaft 4 takes place via a V-belt 10′ of a pulley 10.

A dust suction turbine, not represented, arranged outside of the surface to be sanded, is driven by a drive motor, also not represented, which in turn is controlled by the control device 7. The generated suction pressure conveys the dust from sanding, which was flung outward by the sanding disk 5′ of the sanding plate 5, through a ring-shaped dust suction nozzle 11 arranged around the sanding plate 5 and through a suspended flexible tube arrangement 12 into a dust bag, not represented. By means of this the abrasive grain on the sanding disk 5′ is prevented from becoming melted because of the high sanding speed. The movement of the air is forced by centrifugal force generated by the grinding plate 5, which has an opening toward the sanding shaft 4 in the center.

The sanding machine has three wheels, wherein each one of wheels 13 embodied as running wheels is respectively provided on the left and right sides of the front frame elements 2′ closely behind the sanding plate 5. The rear wheel, embodied as a driving rear wheel 14 is seated in the rear frame element 2″ by means of a rotatable shaft 15, which is driven by a gear motor 17 via a servo arrangement 16.

Steering and directional changing of the sanding machine 1 is achieved by the perpendicular shaft 15 being able to rotate around its axis of rotation.

The sanding machine 1 is put into operation in the wall area of the room to be sanded, and a laser scanner 18, which is attached to the front of the front frame element 2′, has an opening angle of at least 180° and a laser distance sensor, not represented, and a rotating mirror, not represented, is used for measuring the lateral and frontal distance of the sanding machine from the wall. The laser scanner 18 reports the angular position and distance relative from the wall of the sanding machine 1 to the control device 7 via a data interface. In this case, the rotating mirror is used for deflecting the laser beam, so that the wall areas are scanned in a fan fashion.

Lateral sensors applied to the front of the sanding machine 1 function as emergency shut-off devices and prevent the sanding machine 1 from touching the wall. 

1. A floor sanding machine having a frame which supports a motor-driven, height-adjustable sanding plate with a sanding disk on its underside, with a ring-shaped dust suction nozzle surrounding the sanding plate and with two front running wheels, as well as one rear wheel supporting the frame, wherein a control device is provided, which evaluates the signals of a distance-measuring arrangement for measuring the lateral and front distance of the sanding machine from the wall and controls the rear wheel designed as a tail wheel and a rear wheel drive motor by means of a servo device for propelling the sanding machine, wherein a device for adjusting the contact pressure of the sanding plate, as well as the drive motor of the sanding plate, are also controllable by means of the control device, wherein the distance-measuring arrangement has a laser scanner (18) with a laser distance sensor and a rotating mirror, wherein the laser scanner (18) transmits the measuring signals to the control device (7) via a data interface, that a sanding dust suction turbine, which can be controlled by the control device (7), is arranged outside of the area to be sanded, and the dust suction nozzle (11) of the sanding machine is connected with a dust bag of the suction turbine via a suspended suction line (12), and that a frame element (2′) of the sanding machine (1) supporting the sanding plate (5) is releasably connected with a frame element (2′), which supports the tail wheel (14) together with the drive motor (16).
 2. The floor sanding machine in accordance with claim 1, wherein the sanding plate (5) is connected with a hollow shaft (4) embodied in a cylinder shape and having an opening toward the hollow shaft (4) in its center, wherein the hollow shaft (4) is preferably seated in a guide element (6) attached to the underside of the front frame element (1).
 3. The floor sanding machine in accordance with claim 1, wherein the rear wheel (14) is seated on the underside of the rear frame element (2″), preferably rotatable by means of a vertical shaft (15).
 4. In a floor sanding machine having a sanding plate carried for operating contact with an underlying floor surface and propellable along the floor surface on wheels driven by a drive motor, a frame comprising a first frame element carrying the sanding plate and a second frame element, said first and second elements being releasably connected to form the frame, and said second frame element carrying a wheel driven by the drive motor for propelling the floor sanding machine along the floor surface; a controller connected to said drive motor for selectively operating the drive motor to propel the floor sanding machine along the floor surface; a laser scanner carried on said first frame element for scanning wall surfaces located in front of and laterally about the frame and connected to said controller for communicating to said controller measuring signals from the laser scanner for use by said controller in identifying proximately-located wall surfaces and selectively operating the drive motor to avoid contact of the frame with said identified wall surfaces as the floor sanding machine is propelled along the floor surface; and a sanding dust suction removal arrangement carried on said first frame for removing, from an area proximate the sanding plate, dust created by operating contact of the sanding plate with the floor surface, said sanding dust suction removal arrangement comprising a duct carried on said first frame for delivering the removed dust to a collection bag disposed externally of said frame.
 5. In a floor sanding machine in accordance with claim 4, said laser scanner being connected to said controller by a data link comprising a wireless Bluetooth link. 